Typewriter erasing attachment



July 1, 1938. BOOTH 2,123,877

TYPEWRITER ERASINGATTACHMENT Filed Feb. 18, 1936 5 Sheets-Sheet l July39 938., M. BOOTH TYPEWRITER ERAS ING ATTACHMENT Filed Feb. 18, less :5Sheets-Sheet 2 Jufiy H9, M, BOOTH 2,123,877

TYPEWRITER ERASING ATTACHMENT Filed Feb. 18, 1936 3 Sheets-Sheet 3 4 I,INV NTZ WWW;

Patented July 19, 1938 UNITED STATES PATENT OFFICE 15 Claims.

This inventionrelates to an erasing attachment for a typewriter and hasfor its object to provide a. device of this class which is convenient tomove into position for erasing some portion of typewriting, which isalso convenient to be moved out of the way when not in use, and which isconvenient to operate.

Another object is to provide such a device in which the rubber-likeeraser is mechanically mounted and moved in a manner to preclude itsbecoming loaded as erasers are prone to become.

Referring to the drawings, Fig. 1 is a top plan view of a typewriter towhich the attachment of this invention has been applied.

Fig. 2 is a section on the line 2--2 of Fig. 1.

Fig. 3 is a view of the device of Fig. 2 looking in the direction of thearrow 3.

Fig. 4 is a view of the device of Fig. 2 looking in the direction of thearrow 4.

Fig. 5 is a view on the line 5-5 of Fig. 4.

Fig. 6 shows the removable erasing wheel and its shaft.

Fig. 7 shows the mounting for this device on the top of the typewriter,as on line 1-1 in Fig. 1. I

In Fig. 1 some usual form of typewriter is provided with a platen l0 andguide rolls H, for the paper [2. The usual type bars 13 are providedwith centering guides 14 therefor. The ribbon is illustrated at E5.

The device of this invention. includes an arm ill secured to the top ofa typewriter by set screws i6 as shown in Figs. 1 and 7, clamping thearm to a portion of the top of the typewriter. The arm I8 is pivotallysecured at H! to the arm I! and carries at its outer end portion theerasing attachment which is adapted to be swung back to the dotted lineposition 38 indicated in Fig. 1 and conveniently swung with one hand tothe operating position shown in full lines in Fig. 1. On the arm I8 ismounted a presser foot 20, the bottom portion 2i of which is curved toengage and contact with the paper and platen. Journalled in this presserfoot abutment is a shaft 22 carrying the erasing wheel 23 of rubber ofsimilar material preferably shaped to coincide with the cylindricalsurface of the platen. In use. the periphery of the erasing wheel 23 asit wears will continue to conform to the curvature of the platen againstwhich it presses during the erasing operation.

An upstanding wall 24 of the presser foot has attached thereto a stud 25about which may be rotated the actuating handle 26 which is secured tothe pivotal rack 21. The teeth of the rack 21 engage the teeth of thepinion 28 on the eraser shaft 22. It will be seen that the teeth of therack 21 could extend entirely around the stud 25 omitting the handle 23,and the mechanism could then be actuated by thumbing the 5 teeth insteadof grasping the handle.

A stop pin 29 is secured to the wall 24 for the purpose of being engagedby the projection 30 of the oscill'atable rack 27.

As shown in Fig. 5 a spring 3| engages a notch 10 in the wall 24, thenpasses around the screw 32 and has an end portion 33 extending over andin contact with the shaft 22 for pressing the shaft against the bottomof its guideslot hearing.

The presser foot 23 and bottom portion 2| are 15 shown in Figs. 2 and 3as being provided with guide slots 34 and 35 in which the shaft 22 mayhave limited sliding or tilting movement. The reduced portion 36 of theshaft 22 constitutes a guide recess in which the end portion 33 of 20the spring 3| is retained.

On the side of the bracket surrounding the erasing Wheel is provided alug 31 which is adapted to cooperate with and be centered by the typebar centering device l4, so that the eras- 26 ing wheel may beaccurately positioned longitudinally of the platen when the attachmentis initially mounted in the typewriter. Thereafter the lug serves tomaintain such alignment during the erasing operation. The length of thearm I8 80 and the engagement between the platen and presser-foot,contribute to angularly locate the position of the erasing wheel withrespect to the platen.

. Inuse, whenan operator has made a mistake as which she wishes to rubout, it is only necessary to swing the device from the dotted lineposition 38 shown in Fig. 1 to the full line position of Fig. 1 with thepresser foot 20 spaced from the platen, the lug 31 cooperating with thetype bar 40 centering means, and wheel 23 contacting the paper l2. Withthe device in the position illustrated in Fig. 1 the operator may thenwith one hand move the actuating handle 26 back and forth, oscillatingit about its pivot 25, the thrust being transmitted to the platen by thepresser foot and to the centering device I 4 by the bracket carrying thelug 37. The wheel 23 is then responsive to the pressure of the spring3|. Movement of the rack 21 and actuating handle 28 in acounter-clockwise direction is limited as shown in Fig. 3 by engagementof the pin and the lug 30 on the oscillating rack or handle. On movingthe actuating handle 26 in a clockwise direction as shown in Fig. 3, therack 21 meshing with the pinion 23 causes the erasing wheel 23 to berotated. The direction of thrusts applied to the pinion 23 and its shaft22 tend to maintain the shaft 22 in the bottom of its elongated guideslot 34. when the actuator handle 26 and the rack 21 are rotated in acounter-clockwise direction as shown in Fig. 3 the shaft 22 is raised inits guide slot 34. The spring arm 33, however, presses against the shaft22 and tends to hold the erasing wheel shaft adjacent the bottom of itsguide slot 35 with the result that the pinion end portion of the shaft22 is raised slightly causing the shaft to tilt or vibrate to a limitedextent during the erasing operation. It is this floating or vibratoryaction of the shaft 22 which causes the pressure to be applied first onone side of the erasing wheel 23 and then on the other side. Thisshifting of pressure on the erasing wheel is effective in preventing thewheel from becoming loaded with particles of paper or the like as rubbererasers are prone to do when used without being shifted or flexedsufilciently to keep them from doing so. The area of the paper which isin cooperation with the wheel becomes of an oval shape with the longerside extending transversely of the platen. While this erasing attachmentis simple and convenient in operation, being adapted for use with onlyone hand, it should be understood that it operates only upon the ribboncopy. The slight pressure applied to the erasing wheel is sufficient tocause a small blur to occur on carbon copies and this indicates whatletters are to be erased later by hand on the carbon copies, the blurserving as a signal or mark to the operator when' looking at the carboncopy. In the position shown in Fig. 1 the device is adapted to eraseonly one number or letter, but when'more than one are to be erased, itis necessary to move the carriage backward or forward as may be desiredin order to bring other portions of the writing, which are to be erased,under the rotating erasing wheel. As shown in Fig. 2, the erasing wheel23 and its shaft 22, including the pinion 28 may be'readily removable asa unit from the presser foot by simply raising the erasing wheel and itsshaft against the action of the spring arm. 33 until the shaft is clearof its elongated guide slot mounting 35, and then withdrawing. the otherend portion of the shaft 22 out of its guide slot bearing 34. A reversemovement is all that is necessary to replace another erasing wheel andshaft.

If it. were not for the presence of means to take most of the thrust ofoperation off the erasing wheel, the latter would immediately wear ahole through the paper. The thrust is taken by the presser foot and alsoby the surfaces on each side of the centering lug which engages thecentering device for the type bars, so that the only thrust transmittedto the erasing wheel is that imposed by the spring 3| when the saidwheel is pressed against the platen by the thrust of operation andthereupon moved in opposition to said spring. The actuating forceapplied to the rack 21 causes the pinion-28 and its shaft 22 to beraised and lowered in the elongated bearing 34. This results in arocking or tilting movement given to the erasing wheel 23 as the pinionend of the shaft 22 is moved along the elongated bearing slot 34, suchrocking movement taking place substantially about the bearing 35 as apivot. Due to the slot 34 being directed away from the platen at anangle as shown, for example, in Fig. 3, the erasing wheel not only hasthe rocking or tilting movement just referred to, but also has atwisting or changing of the plane of the erasing wheel due to saidrocking or tilting. In other-words, in Fig. 2 the erasing wheel not onlyrocks or tilts slightly so that first one edge and then the other bearsagainst the paper and platen, but also twists slightly so that the planeof the erasing wheel as shown in Fig. 2 changes slightly from a positionnormal to the paper. Due to these tilting and twisting movements, thecurvature of the eraser does not wear to the precise curvature of theplaten but only substantially so.

I claim:

1. An erasing attachment for a typewriter comprising a rotatable erasingwheel capable of I a vertical inclination adapted to wear concavely onits periphery to substantially the curvature of the typewriter platen,means for mounting said erasing wheel to be swung to one side out of theway when not in use and means for oscillating said erasing wheel when inoperative position, and means for changing the vertical inclination ofthe erasing wheel axis and bearing harder on one peripheral end portionof the erasing wheel and then on the other during operation, to flex theerasing wheel slightly and keep the same from becoming loaded.

2. An erasing attachment for a typewriter comprising a support, an armpivoted thereto for movement toward and from the platen, a presser footsecured to said arm and shaped to bear against the paper and platen, anerasing wheel carried by said presser foot with its axis spaced from andsubstantially normal to the platen axis,

actuating and transmission mechanism also car-- ried by said presserfoot for manually oscillating said erasing wheel.

3. An erasing attachment for a typewriter comprising a support, an armpivoted thereto for movement toward and from the platen, a presser footsecured to said arm and shaped to bear against the paper and platen, anerasing wheel carried by said presser foot with its axis spaced from andsubstantially normal to the platen axis, actuating and transmissionmechanism also carried by said presser foot for oscillating said erasingwheel, and a guide lug also carried by said presser foot for cooperationwith the type bar centering device to align said erasing wheel with saidcentering device.

4. An erasing attachment for a typewriter comprising a support, an armpivoted thereto for movement toward and from the platen, a presser footsecured to said arm and shaped to bear against the paper and platen, anerasing wheel carried by said presser foot with its axis spaced from andsubstantially normal to the platen axis, actuating and transmissionmechanism also carried by said presser foot for oscillating said erasingwheel, said erasing wheel being yieldably mounted on said presser footto compensate for wear of the wheel.

5. An erasing device for a typewriter comprising a rotatable erasingwheel having its axis spaced from and extending substantiallytransversely of the platen, wherebyv the wheel is adapted to wear itsperiphery concave to conform to the curvature of the platen, means forpositioning said wheel longitudinally and angularly of the platen, andmeans for mounting and actuating said wheel so that the area of paper onthe 6. An erasing attachment for a typewriter comprising a support, anarm pivoted thereto for movement toward and from the platen, a presserfoot carried by said arm and shaped to bear against the paper andplaten, an erasing wheel carried by said presser foot with'its axisspaced from and substantially normal to the platen axis, actuating andtransmission mechanism also carried by said presser foot for oscillatingsaid erasing wheel, said arm and presser foot being adapted to be swungto a position back from the platen and out of the way over thetypewriter where it is adapted to be held by gravity, the movements ofsaid arm and the actuation of said wheel being efiected by one hand ofthe operator.

'7. An erasing attachment for a typewriter comprising an erasing wheelof rubber or. the like, means for positioning said wheel longitudinallyand angularly of the platen, and means for mounting and actuating saidwheel in such manner that the wheel and its axis may vibrate to keepfrom becoming loaded in use and to vary the pressure between the paperand wheel across the wheel rim. 1

8. An erasing attachment for a typewriter comprising a support, an armpivoted thereto for movement toward and from the platen, a presser footsecured to said arm and shaped to bear against the paper and platen, anerasing wheel and shaft therefor carried by said presser foot with itsaxis spaced from and substantially normal to the platen axis, anactuating handle and transmission mechanism also carried by said presserfoot for oscillating said erasing wheel, said actuating handle beingjournalled in said presser foot, and said transmission mechanismincluding an arcuate rack to which said handle is secured and a pinionfixed on the shaft of said erasing wheel and meshing with said rack.

9. An erasing attachment for a typewriter comprising a support, an armpivoted thereto for movement toward and from the platen, a presser footforming a part of said arm and shaped to bear against the paper andplaten. an erasing wheel and shaft therefor carried by said presser footwith its axis spaced from and substantially normal to the platen axis,actuating and transmission mechanism also carried by said presser footfor oscillating said erasing wheel, and said mechanism including anarcuate rack and a pinion fixed on the shaft of said erasing wheel andmeshing with said rack and a spring iixed to said presser foot andengaging one end portion of the erasing wheel shaft to press the wheelagainst said paper and platen. said erasing wheel shaft being supportedin a slotted guide so that on movement of said handle in one directionsaid erasing wheel shaft is rotated at the end of said guide jacent theplaten and on movement of said handle in the opposite direction, theerasing wheel shaft is moved in said guide against the action of saidspring to tilt the erasing wheel slightly and shift the pressure betweenthe wheel and paper on the platen enough to keep the erasing wheel frombecoming loaded.

10. An erasing attachment comprising an erasing wheel, means for movingthe eraser with respect to a paper, means for holding the paper duringthe erasing operation, means for rocking or tilting the plane of theeraser with respect to the paper during each erasing movement, and meansfor changing the place of maximum pressure contact between the erasingwheel and paper across the rim of said erasing wheel.

- 11. The combination with an eraser of rubberlike material, of meansfor moving said eraser back and forth during an erasing operation, andmeans for mounting said eraser material in a manner to tilt the same andits axis to prevent it becoming loaded during the erasing operation.

12. The combination with an eraser of a rubber-like material, of meansfor moving said eraser back and forth during an erasing operation, andmeans for mounting said eraser material in a manner to tilt the same andits axis to prevent it becoming loaded during the erasing operation, andmeans for supporting the same from a typewriter and longitudinally andangularly positioning the eraser with respect to the platen of atypewriter, said last-mentioned means being adapted to enable the eraserto be swung back out of the way when not in use.

13. An erasing attachment for a typewriter comprising an erasing wheel,means for yieldably mounting the wheel, a support for said wheel andmeans, means for positioning the wheel longitudinally of the platen andincluding a lug adapted to fit between the type bar centering guides,means for actuating said wheel, and means for positioning said wheelangularly with respect to the platen surface and including a support oneach side of said lug adapted to rest upon the top of the type barcentering guides.

14. An erasing attachment for a typewriter comprising an erasing wheel.means for yieldably mounting the wheel, means for positioning the wheellongitudinally of the platen and including a lug adapted to fit betweenthe type bar centering guides, means for actuating said wheel, means forpositioning said wheel angularly with respect to the platen surface, andmeans for supporting said wheel, and including a support contiguous thetype bar centering guides and another support curved to conform to thesurface of the platen.

15. An erasing attachment comprising an eraser, means for moving theeraser with respect to a paper, means for holding the paper during theerasing operation, means for rocking or tilting the plane of the eraserwith respect to the paper during each erasing movement, and means fortwisting or changing the plane of the eraser in addition to the changein the plane of the eraser due to the rocking or tilting motion duringthe erasing operation.

MARGARET BOOTH.

